Hello, i've found this projects (http://forum.allaboutcircuits.com/showthread.php?t=90721)
i'd like use this circuit in a pc case mod with leds ropes (30blue led SMD 2.4W 12Vcc with a 170 ohm resistor each 3leds) but i'm going to use just 18 leds on npn and 18 on pnp(6segments*3leds).
... i have a few question and request (original circuit and part list http://www.simple-electronics.com/2011/09/fading-led.html):
_the original circuit is for 9vdc but the ne555 power range is up to 16V dc; since the 12v should be stabilized from the pc supply unit, can i use the 555 on 12v ?
_the npn and pnp transistor from the original project are general purpose (9012;9013) and im not sure if they can handle the current for 18 leds each side so i need some help picking the right transistor.
_am i right if i replace the red circle parts with the leds rope since there are already 170 ohm resistor on it ?
_the fading time should be around 3-4sec, can i change the 20k resistor and the 220uF to play with the fading time or i'll damage the 555 ?
i did some learning from Bill_Marsden's post about LEDs, 555s, Flashers, and Light Chasers but for the moment i cant sort this out without help.
Thanks a lot for your time!
i'd like use this circuit in a pc case mod with leds ropes (30blue led SMD 2.4W 12Vcc with a 170 ohm resistor each 3leds) but i'm going to use just 18 leds on npn and 18 on pnp(6segments*3leds).
... i have a few question and request (original circuit and part list http://www.simple-electronics.com/2011/09/fading-led.html):
_the original circuit is for 9vdc but the ne555 power range is up to 16V dc; since the 12v should be stabilized from the pc supply unit, can i use the 555 on 12v ?
_the npn and pnp transistor from the original project are general purpose (9012;9013) and im not sure if they can handle the current for 18 leds each side so i need some help picking the right transistor.
_am i right if i replace the red circle parts with the leds rope since there are already 170 ohm resistor on it ?
_the fading time should be around 3-4sec, can i change the 20k resistor and the 220uF to play with the fading time or i'll damage the 555 ?
i did some learning from Bill_Marsden's post about LEDs, 555s, Flashers, and Light Chasers but for the moment i cant sort this out without help.
Thanks a lot for your time!